<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>计算器</title>
    <link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
</head>

<body>
    <div class="container">
        <!-- 计算器 -->
        <div class="panel panel-primary">
            <div class="panel-heading">计算器（输入两个数进行加减乘除运算）</div>
            <div class="panel-body">
                <div class="input-group">
                  <input type="number" class="form-control" placeholder="第一个数" id='num1'/>
                </div>
                <!--运算符-->
                <select id="oper" class="form-control operation">
                    <option value="+">+</option>
                    <option value="-">-</option>
                    <option value="*">*</option>
                    <option value="/">/</option>
                </select>
                <!-- 数字2 -->
                <div class="input-group">
                  <input type="number" class="form-control" placeholder="第二个数" id='num2'/>
                </div>
                <!--等于-->
                <button type="button" class="btn btn-success" onclick="operation()">=</button>
                <!--结果-->
                <div class="input-group result">
                    <input type="text"  class="form-control"  id='result'/>
                </div>
            </div>
        </div>
    </div>
    <script type="text/javascript" src="js/index.js"></script>
</body>

</html>
